# Two Formulas for Mid-Point Progression

**Overview**

There are 2 formulas to determine the mid-point progression or mid-point differential.

**Formula One**

The first formula expresses the differentials between adjacent mid-points in dollar value:

Midpoint of the Next Grade = (Midpoint of Lower Grade X Midpoint Differential) + Midpoint of Lower Grade

Example

Midpoint of Lower Grade = $30,000

Midpoint Differential = 10%

Midpoint of the Next Grade = ($30,000 X 10%) add $30,000 = $33,000

**Formula Two**

The second formula expresses the differentials between adjacent mid-points as a percentage or a ratio.

The formula for calculating it as a ratio is as follows:

Midpoint of the Next Grade less Midpoint of Lower Grade / Midpoint of Lower Grade

That is (Mid B – Mid A) / Mid A

Example

Mid-point of the Next Grade = $33,000

Mid-point of Lower Grade = $30,000

Mid-point Differential = ($33,000 less $30,000) / $30,000 = 0.1

This is 10%